Uncoupling and Endocytosis of 5-Hydroxytryptamine 4 Receptors

Barthet, Gaël; Gaven, Florence; Framery, Bérénice; Shinjo, Keiko; Nakamura, Takaaki; Claeysen, Sylvie; Bockaert, Joël; Dumuis, Aline

doi:10.1074/jbc.m502272200

Cited by 46 publications

(24 citation statements)

References 60 publications

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“…Moreover, overexpression of GRK2 significantly decreases serotonin-induced cAMP generation in these cells, suggesting a negative regulatory role for GRK2 at the 5-HT4R. A similar effect was also seen for variants of the 5-HT4R, including the 5-HT4A, 5-HT4B, 5-HT4E and 5-HT4F receptors, which displayed less G protein-coupling when GRK2 was overexpressed in COS-7 cells (Barthet et al , 2005). …”

Section: Serotonin 4 Receptor Signaling and Regulation Via β-Arrestinsmentioning

confidence: 78%

Serotonin receptor signaling and regulation via β-arrestins

Bohn¹,

Schmid²

2010

Critical Reviews in Biochemistry and Molecular Biology

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Serotonin receptors are the product of 15 distinct genes, 14 of which are G protein-coupled receptors. These receptors are expressed in a wide range of cell types, including distinct neuronal populations, and promote diverse functional responses in multiple organ systems. These receptors are important for mediating the in vivo effects of their cognate neurotransmitter, serotonin, as well as the endogenous tryptamines. In addition, the actions of many drugs are mediated, either directly or indirectly, through serotonin receptors, including antidepressants, antipsychotics, anxiolytics, sleep aids, migraine therapies, gastrointestinal therapeutics and hallucinogenic drugs. It is becoming increasingly evident that serotonin receptors can engage in differential signaling that is determined by the chemical nature of the ligand and that ligands that demonstrate a predilection for inducing a particular signaling cascade are considered to have “functional selectivity”. The elucidation of the cellular signaling pathways that mediate the physiological responses to serotonin and other agonists is an active area of investigation and will be an onward-looking focal point for determining how to effectively and selectively promote beneficial serotonergic mimicry while avoiding unwanted clinical side effects. This review highlights the modulation of serotonin 2A, 2C, and four receptors by β-arrestins, which may represent a fulcrum for biasing receptor responsiveness in vivo.

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Section: Serotonin 4 Receptor Signaling and Regulation Via β-Arrestinsmentioning

confidence: 78%

Serotonin receptor signaling and regulation via β-arrestins

Bohn¹,

Schmid²

2010

Critical Reviews in Biochemistry and Molecular Biology

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“…Cross-linking was carried out in phosphate-buffered saline (PBS) completed with 25 mM of dithiobis(succinimidyl propionate) (Pierce) for 30 min, as described previously (33). After 60 min of incubation at 4°C, samples were processed as described (29), using a 1:1 mixture of Protein A/Protein G-Sepharose beads (GE Healthcare) that were precoupled with 8 g of antiMyc antibody (Polyclonal A-14, Santa Cruz Biotechnology, Inc.). Immunoprecipitated proteins were eluted in Laemmli sample buffer, resolved by SDS-PAGE, and detected by Western blotting.…”

Section: Methodsmentioning

confidence: 99%

“…Plasmid Constructs-Tagged-5-HT 4(a) R cDNA plasmids in pRK5 were generated by adding the c-Myc, HA, FLAG, or RhoTag epitopes to the N-terminal extremity of the receptor using the QuikChange site-directed mutagenesis kit (Stratagene, Amsterdam, The Netherlands) as described previously (29). Tagged 5-HT 4 R-D100A (D100A), 5-HT 4 R-D66N (D66N), 5-HT 4 R-D66N/D100A (DD), 5-HT 4 R-T104A (T104A), and 5-HT 4 R-D330Stop (⌬329) mutants were generated from tagged 5-HT 4(a) R cloned in pRK5 using the same mutagenesis kit.…”

Section: Methodsmentioning

confidence: 99%

“…Twenty-four hours after transfection, a 10-min (cAMP) or 30-min (IP1) stimulation with the appropriate concentrations of drugs was performed as described previously (29). cAMP or IP1 production was quantified by HTRF using the cAMP Dynamic kit or the IP-One kit (Cisbio International, Bagnols-sur-Cèze, France), according to the manufacturer's instructions.…”

Section: Co-immunoprecipitation Experiments and Immunoblotting-mentioning

confidence: 99%

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G Protein Activation by Serotonin Type 4 Receptor Dimers

Pellissier

Barthet

Gaven

et al. 2011

Journal of Biological Chemistry

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The discovery that class C G protein-coupled receptors (GPCRs) function as obligatory dimeric entities has generated major interest in GPCR oligomerization. Oligomerization now appears to be a common feature among all GPCR classes. However, the functional significance of this process remains unclear because, in vitro, some monomeric GPCRs, such as rhodopsin and ␤ 2 -adrenergic receptors, activate G proteins. By using wild type and mutant serotonin type 4 receptors (5-HT 4 Rs) (including a 5-HT 4 -RASSL) expressed in COS-7 cells as models of class A GPCRs, we show that activation of one protomer in a dimer was sufficient to stimulate G proteins. However, coupling efficiency was 2 times higher when both protomers were activated. Expression of combinations of 5-HT 4 , in which both protomers were able to bind to agonists but only one could couple to G proteins, suggested that upon agonist occupancy, protomers did not independently couple to G proteins but rather that only one G protein was activated. Coupling of a single heterotrimeric G s protein to a receptor dimer was further confirmed in vitro, using the purified recombinant WT RASSL 5-HT 4 R obligatory heterodimer. These results, together with previous findings, demonstrate that, differently from class C GPCR dimers, class A GPCR dimers have pleiotropic activation mechanisms. G protein-coupled receptors (GPCRs)2 are key players in cell-cell communication. They transduce a wide range of extracellular signals, such as light, odors, hormones, or neurotransmitters into appropriated cellular responses (1, 2). Signal transduction occurs via conformational changes of the ligandactivated GPCRs, leading to activation of G proteins and their downstream signaling pathways (3).GPCRs have been considered for a long time as monomeric proteins, and the paradigm of "one ligand/one receptor/one G protein" was the driving principle (1). However, a growing number of studies revealed dimerization/oligomerization of GPCRs (4 -8) mostly in heterologous cells (homo-or heterodimers) but also in native tissues or in vivo (dimers) (9 -13). In line with these observations, a recent report described crystal structures of the chemokine receptor CXCR4 that are consistent with the formation of homodimers (14).A relatively accepted model proposes that only one protomer in a dimer is fully activated, even when both binding sites are occupied (15)(16)(17)(18)(19). The activated protomer interacts with the G␣ subunit to accelerate GDP/GTP exchange. This is compatible with recent data showing that a rhodopsin monomer (or a ␤ 2 -adrenergic receptor monomer) is sufficient to activate its cognate G protein after purification and reconstitution in a phospholipid bilayer (20, 21). However, some observations indicate that the active state of a GPCR dimer is asymmetric (22, 23) and that conformational switches occur between protomers (24, 25). Moreover, occupation of the second protomer of a dimer is probably not "silent" because it can either favor (26) or reduce (22) coupling efficiency. It has also ...

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“…The levels of cAMP were analyzed after the injection of NaCl (9‰) or BIMU8 (4 ϫ 10 Ϫ4 g/l) into the NAc of WT mice. The protocol (40) included a combined i.p. injection of the phosphodiesterase inhibitor rolipram (0.2 mg/kg).…”

mentioning

confidence: 99%

Anorexia induced by activation of serotonin 5-HT ₄ receptors is mediated by increases in CART in the nucleus accumbens

Jean

Conductier

Manrique

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

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176

142

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Anorexia nervosa is a growing concern in mental health, often inducing death. The potential neuronal deficits that may underlie abnormal inhibitions of food intake, however, remain largely unexplored. We hypothesized that anorexia may involve altered signaling events within the nucleus accumbens (NAc), a brain structure involved in reward. We show here that direct stimulation of serotonin (5-hydroxytryptamine, 5-HT) 4 receptors (5-HT4R) in the NAc reduces the physiological drive to eat and increases CART (cocaine-and amphetamine-regulated transcript) mRNA levels in fed and food-deprived mice. It further shows that injecting 5-HT4R antagonist or siRNA-mediated 5-HT4R knockdown into the NAc induced hyperphagia only in fed mice. This hyperphagia was not associated with changes in CART mRNA expression in the NAc in fed and food-deprived mice. Results include that 5-HT4R control CART mRNA expression into the NAc via a cAMP/PKA signaling pathway. Considering that CART may interfere with food-and drug-related rewards, we tested whether the appetite suppressant properties of 3,4-N-methylenedioxymethamphetamine (MDMA, ecstasy) involve the 5-HT4R. Using 5-HT4R knockout mice, we demonstrate that 5-HT4R are required for the anorectic effect of MDMA as well as for the MDMA-induced enhancement of CART mRNA expression in the NAc. Directly injecting CART peptide or CART siRNA into the NAc reduces or increases food consumption, respectively. Finally, stimulating 5-HT4R-and MDMA-induced anorexia were both reduced by injecting CART siRNA into the NAc. Collectively, these results demonstrate that 5-HT4R-mediated upregulation of CART in the NAc triggers the appetite-suppressant effects of ecstasy.A norexia nervosa is one of the mental diseases exhibiting the highest mortality rates in industrialized countries (1, 2). No effective strategies for treating this disorder are available. If one defines anorexia as self-imposed deprivation despite an energy demand, similar behavior can be provoked by treatments that increase serotonin (5-hydroxytryptamine, 5-HT) neuromodulation (3). For instance, fenf luramine, which increases synaptic 5-HT levels, lowers the consumption of food in humans and rodents (4, 5). Similarly, amphetamine and 3,4-N-methylenedioxymethamphetamine (MDMA, ecstasy) diminish food consumption in humans (6) and rats (7) and reduce deprivation-induced eating in mice (8). 5-HTinduced hypophagia is mediated by both 5-HT 1B and 5-HT 2C receptors (5-HT 1B R and 5-HT 2C R) (9 -11). In particular, 5-HT 2C R in the hypothalamus contributes to fenf luramineand MDMA-induced anorexia-like behavior (5, 8, 12). Moreover, 5-HT 1B R and 5-HT 2C R knockout (KO) mice are less sensitive to fenf luramine (4, 5).Stress and anxiety can also induce anorexia (13), and increases in 5-HT neuromodulation are known to participate in the decreased food intake caused by stress (14-16). We have demonstrated that 5-HT 4 R KO displays attenuated responses to stress-induced hypophagia (17). Because MDMA is a rewarding drug that reduces the intake of food...

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Uncoupling and Endocytosis of 5-Hydroxytryptamine 4 Receptors

Cited by 46 publications

References 60 publications

Serotonin receptor signaling and regulation via β-arrestins

Serotonin receptor signaling and regulation via β-arrestins

G Protein Activation by Serotonin Type 4 Receptor Dimers

Anorexia induced by activation of serotonin 5-HT ₄ receptors is mediated by increases in CART in the nucleus accumbens

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Uncoupling and Endocytosis of 5-Hydroxytryptamine 4 Receptors

Cited by 46 publications

References 60 publications

Serotonin receptor signaling and regulation via β-arrestins

Serotonin receptor signaling and regulation via β-arrestins

G Protein Activation by Serotonin Type 4 Receptor Dimers

Anorexia induced by activation of serotonin 5-HT 4 receptors is mediated by increases in CART in the nucleus accumbens

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Product

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Anorexia induced by activation of serotonin 5-HT ₄ receptors is mediated by increases in CART in the nucleus accumbens